A commentary on digital photography news and practice based on my ongoing photo magazine coverage of the industry and photographer community since 1975.

Wednesday, November 12, 2008

Color Management - A Necessary Evil?

In this month's (December) issue of Shutterbug I have an article on page 68 initiated by a number of e-mail questions to Digital Help asking about various aspects of one problem: getting prints that match the image on your computer screen. Soon after the issue hit the newsstands I was informed that "prints too dark" was a big issue on the Adobe web site with over a hundred posts, and there were pages of references to it on Google. Some, and not just a few were a little angry that their printer manufacturer's support was helpless, and as far as I read there were few in the Adobe Forum who had any clues.

Fortunately a couple of years ago or so, doing some beta testing for color management products, I saw the possibility of this problem arising. But no one at the time was interested - they should be now! It's not your printer's fault, nor is it caused by the printer driver, or for that matter your operating system or the photo image editing application you are using. The cause of the problem "my prints are too dark" is your visual perception has been deceived by the nice bright new LCD display connected to your computer. I am not sure but I doubt any of those still using a big, heavy old CRT monitor, are among those reporting this print/screen mismatch problem.

Why LCD displays are at the root of this is they are half again or more brighter than a CRT, and a CRT's range of brightness almost exactly matches the range of reflective brightness in a print. Let me put it this way, imagine there are two ladders side by side, one 10 feet high, the other 15 feet. If you climb up half way on the 15 foot ladder and look across at the 10 foot ladder you will be looking at the top rungs of the 10 foot ladder, and vice versa, if you climb half way up the 10 foot ladder you will be looking at the lower rungs of the 15 foot ladder. This is the situation you have with an LCD display. When you color correct and adjust either Raw camera files or scans of film, one of the things you do to make it look ideal to your perception is to adjust the image brightness. This establishes the location of the image midpoint in Photoshop's Levels, or what you do with a slider in Elements or LightRoom to adjust image brightness. But when that information as to the location of the image's midpoint brightness value is conveyed to your printer it "assumes" the information is coming from a brightness range that is the same as the printer's, which reproduces a smaller brightness range, and there is a mismatch and the printer reproduces the image with its midpoint much lower than it should be. By the way, if the print is made so the printer driver manages color and not the application using Color management, too dark prints do not result because the driver is adjusting the image, but then usually the color does not match what's on your screen.

The workaround or fix I recommended in the Shutterbug workflow article is the Transfer Function Output option that is available in the Print (preview) window dialogue of all Adobe Photoshop CS versions, which supports compensating to output a brighter print. But what about photographers using Adobe LightRoom or Photoshop Elements, and Apple users printing from Aperture or iPhoto? There are ways to negate the misperception of image brightness with LCD displays so when you are adjusting images the midpoint will be set so the print output will be lighter. One is to adjust the lighting in your computer's environment so the area immediately behind the LCD display is much brighter. This will trick your vision to perceive the screen darker and to then set the image brightness higher. Another way to accomplish the same thing is to get a piece of neutral density gel (from a pro camera dealer like Adorama or B&H) that reduce light transmission 50% and put the gel in front of your display screen. You may ask, why not just turn down the brightness of the display? My answer is, to reduce the display brightness enough (and you would lower the contrast control to reduce the white luminance level), I think you will find the image reproduction quality will be muddy and probably unsatisfactory.

Finally, some of the reported problems may have different causes, like choosing the wrong printer profile or some other error in workflow. However, if your situation differs, or you have a solution to suggest, and if you don't have access to a copy of Shutterbug to read the article drop me a line by e-mail at: goofotografx@gmail.com (or, the article will be archived at Shutterbug.com the first week of December.